Returns the unknown parameter given 3 of 4 parameters to calculate respiration rate in a closed respirometer. This is useful both for basic closed respirometry setups, and also for the closed measurement phase of intermittent respirometry.

1 2 | ```
closed(MO2, delta_pO2, duration, vol, temp = 25, sal = 35,
atm_pres = 1013.25)
``` |

`MO2` |
whole-animal oxygen consumption rate (umol O2 / hour). |

`delta_pO2` |
desired change in pO2 (% air saturation). |

`duration` |
desired duration to reach |

`vol` |
volume of the respirometer (liter). |

`temp` |
temperature (°C). Default is 25 °C. |

`sal` |
salinity (psu). Default is 35 psu. |

`atm_pres` |
atmospheric pressure (mbar). Default is 1013.25 mbar. |

If there are more than two O2 observations, consider using `calc_MO2`

.

Matthew A. Birk, matthewabirk@gmail.com

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | ```
# I've read in the literature that my animal has an SMR of 200 umol/h. How large of a
# respirometer do I want if I want it to breathe down to 80% air saturation in 30 minutes?
closed(MO2 = 200, delta_pO2 = 100 - 80, duration = 30) # returns respirometer volume
# I've read in the literature that my animal has an SMR of 1000 umol/h. How long will it take to
# breathe down a 50 L respirometer by 10% air saturation?
closed(MO2 = 1000, delta_pO2 = 10, vol = 50) # returns the duration to breathe down the O2
# How does animal size affect how long my measurement periods last?
mass_range <- seq(100, 400, 50)
dur_range <- (closed(MO2 = scale_MO2(mass_1 = 100, MO2_1 = 400, mass_2 = mass_range),
delta_pO2 = 20, vol = 10))
plot(mass_range, dur_range, type = 'b')
# What is the MO2 if O2 drops 0.44 mg/l in 33 minutes when the respirometer volume is 30 L?
closed(delta_pO2 = conv_o2(o2 = 0.44, from = 'mg_per_l', to = 'percent_a.s.'), duration = 33,
vol = 30)
``` |

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